This application is related to Japanese Patent Application No. 2000-282458 filed in Sep. 18, 2000 whose priority is claimed under 35 USC xc2xa7119, the disclosure of which is incorporated by reference in its entirety.
1. Field of the Invention
The present invention relates to a detector for blood analysis and to a blood analyzer and a blood analyzing method. More particularly, the invention relates to a detector for analyzing white blood cells and red blood cells in a blood sample by an electric resistance method and to a blood analyzer for determination of the numbers and particle size distributions of the white blood cells and the red blood cells.
2. Description of the Related Art
In a conventional blood analyzer of electric resistance type having a flow circuit as shown in FIG. 1, white blood cells and red blood cells are analyzed in the following manner. The flow circuit includes a plurality of fluid devices such as values and pumps which make a network using tubes and nipples.
(1) A negative pressure is applied to a drain chamber 30 with valves V6, V7, V13 being open to discharge residual liquid from a mixing chamber 12, a white blood cell detector 10 and a red blood cell detector 11.
(2) A quantitative sampling pump 3 is driven for suction with a valve V1 being open to suck a predetermined amount of a blood sample into a pipette 1 from a sample container 2.
(3) With valves V2, V8 being open, a valve V5 is switched for communication between an outlet P1 and an inlet P2, and a negative pressure is applied to the drain chamber 30 to suck a diluent into the white blood cell detector 10 from a diluent supplying section 7 for cleaning the white blood cell detector 10. Similarly, with valves V3, V9 being open, the valve V5 is switched for communication between the outlet P1 and the inlet P3, and a negative pressure is applied to the drain chamber 30 for cleaning the red blood cell detector 11.
(4) A diluent pump 4 is driven for suction with the valve V8 being open to suck the diluent into a flow circuit from the diluent supplying section 7. Then, the diluent pump 4 is driven for pressurization with the valve V4 being open and with a valve V8 being closed to inject a predetermined amount of the diluent into the mixing chamber 12. Similarly, the dilution pump 4 is driven for suction with the valve V8 being open and with the valve V4 being closed to suck the diluent into the flow circuit from the diluent supplying section 7. Then, the diluent pump 4 is driven for pressurization with a valve V12 being open and with the valves V8, V4 being closed to inject a predetermined amount of the diluent into the red blood cell detector 11.
(5) The pipette 1 is moved to the mixing chamber 12 by a pipette driver (not shown). Then, the blood sample sucked into the pipette from the sample container 2 in Step (2) is discharged into the mixing chamber 12 by driving the quantitative sampling pump 3 for pressurization with the valve V1 being open. Thus, a blood specimen is prepared in the mixing chamber 12 through first-stage dilution of the blood sample.
(6) The pipette 1 is moved to the mixing chamber 12 by the pipette driver (not shown), and a diluent pump 5 is driven for suction with the valves V1, V45 being open to suck a predetermined amount of the blood specimen obtained through the first-stage dilution into the pipette from the mixing chamber 12. Then, the pipette 1 is moved to the white blood cell detector 10, and the diluent pump 5 is driven for pressurization with the valves V1, V45 being open to discharge the blood specimen into the white blood cell detector 10 from the pipette. This blood specimen is employed for the analysis of the white blood cells.
(7) As in Step (6), the pipette 1 is moved to the mixing chamber 12 by the pipette driver (not shown), and a predetermined amount of the blood specimen obtained through the first-stage dilution is sucked into the pipette from the mixing chamber 12. Then, the pipette 1 is moved to the red blood cell detector 11 by the pipette driver (not shown), and a predetermined amount of the blood specimen obtained through the first-stage dilution is discharged into the red blood cell chamber 11. Thus, a blood specimen is prepared in the red blood cell detector 11 through second-stage dilution. The blood specimen thus prepared in the red blood cell detector 11 is employed for the analysis of the red blood cells.
(8) A valve V10 is switched for communication between an outlet P4 and an inlet P6, and a hemolyzation agent pump 6 is driven for suction to introduce a hemolyzation agent into the flow circuit from a hemolyzation agent supplying section 8. Then, the valve V10 is switched to open the outlet P4 and the inlet P5, and the hemolyzation agent pump 6 is driven for pressurization to inject the hemolyzation agent into the white blood cell detector 10. After a lapse of a predetermined period, hemolyzation is completed in the white blood cell specimen retained in the white blood cell detector 10.
(9) The valve V5 is switched for communication between the outlet P1 and the inlet P2, and a negative pressure is applied to the discharge chamber 30 to suck the white blood cell specimen from the white blood cell detector 10 through an orifice 20. A change in impedance occurring when the white blood cell specimen passes through the orifice 20 is detected by electrodes 13, 14 for determination of the number and particle size distribution of the white blood cells. Similarly, the valve V5 is switched to open the outlet P1 and the inlet P3 to suck the red blood cell specimen from the red blood cell detector 11 through an orifice 21. A change in impedance occurring when the red blood cell specimen passes through the orifice 21 is detected by electrodes 15, 16 for determination of the number and particle size distribution of the red blood cells.
(10) The diluent pump 4 is driven for suction with the valve V8 being open to suck the diluent into the flow circuit from the diluent supplying section 7. Then, the diluent pump 4 is driven for pressurization with the valves V4, V11, V12 being open and with the valve V8 being closed to inject the diluent into the mixing chamber 12, the white blood cell detector 10 and the red blood cell detector 11.
(11) The quantitative sampling pump 3 is driven for suction with a valve V43 being open to suck the diluent into the flow circuit from a diluent supplying section 7. Then, the quantitative sampling pump 3 is driven for pressurization with the valve V1 being open and with the valve V43 being closed to clean a flow path extending from the quantitative sampling pump 3 to the pipette 1. At this time, the diluent flows out of a tip of the pipette 1, and is sucked into the drain chamber 30 in a manner as described in Step (12). On the other hand, the diluent pump 4 is driven for suction with the valve V8 being open to suck the diluent into the flow circuit from the diluent supplying section 7. Then, the diluent pump 4 is driven for pressurization with a valve V40 being open and with the valve V8 being closed to supply the diluent into a cleaning spitz 17. At this time, the diluent flows out of an outlet P10. Thus, the outer periphery of the pipette 1 is cleaned. Then, the diluent is sucked into the drain chamber 30 in the manner described in Step (12). The cleaning spitz 17 has a pipette receptor 27 into which the pipette 1 is inserted. A diluent inlet port 28 for supplying the diluent and a diluent suction port 29 for sucking the diluent are provided in a side wall of the pipette receptor 27.
(12) The cleaning spitz 17 is vertically moved along the pipette 1 by a cleaning spitz driver (not shown). A negative pressure is applied to the drain chamber 30 with a valve V41 being open, whereby the diluent flowing out of the pipette 1 and the outlet P10 in Step (11) is sucked into the drain chamber 30 through the inlet P11. Thus, the inside and outer periphery of the pipette 1 are cleaned.
(13) By performing Steps (1) to (12), the analysis of the blood sample is completed to be ready for the analysis of the next blood sample.
The orifices 20, 21 are each generally formed in a disk of artificial ruby, because they are required to be highly resistant to breakage and chemical agents and to have a high dimensional accuracy. As a material for the electrodes 13, 14, 15, 16 for the detection of the changes in impedance, platinum is employed which is highly resistant to chemical agents. Thus, the materials for the orifices and the electrodes are very expensive, increasing the costs of the conventional blood analyzer in which these components are provided in the white blood cell detector and the red blood cell detector. Since the white blood cell detector and the red blood cell detector are separately provided, the diluent pumps for supplying the diluent and the valves for switching the flow paths should be provided for each of the white blood cell detector and the red blood cell detector. This increases the complexity, size and costs of the analyzer.
In view of the foregoing, the present invention is directed to a detector which can singly achieve easy and accurate analysis of white blood cells and red blood cells. The present invention is further directed to simplification, size reduction and cost reduction of a blood analyzer.
In accordance with the present invention, there is provided a blood cell detector which comprises an orifice section having a single orifice, a first supplying section for supplying a first blood specimen into the orifice section, a second supplying section for supplying a second blood specimen into the orifice section, and first and second electrodes provided on opposite sides of the orifice for detecting a change in impedance of each of the first and second blood specimens when the first and second blood specimens are selectively caused to pass through the orifice.